UITextField设置无法输入空格

1.在UITextFieldDelegate的代理方法中设置过滤空格

- (BOOL)textField:(UITextField *)textField shouldChangeCharactersInRange:(NSRange)range replacementString:(NSString *)string {
    
    NSString *textPsw = [string stringByTrimmingCharactersInSet:[NSCharacterSet whitespaceCharacterSet]];
    if ([textPsw length] == 0) {
        return NO;
    }
    return YES;
}

此时虽然不能输入空格，但是出现点击删除键却无法删除的问题，解决如下：

- (BOOL)textField:(UITextField *)textField shouldChangeCharactersInRange:(NSRange)range replacementString:(NSString *)string {
    
    NSString *textPsw = [string stringByTrimmingCharactersInSet:[NSCharacterSet whitespaceCharacterSet]];
    if (range.length == 1 && textPsw.length == 0) {
        return YES;
    }
    if ([textPsw length] == 0) {
        return NO;
    }
    return YES;
}